High Availability for SAS 9 Metadata Server

Transcription

1 High Availability for SAS 9 Metadata Server White Paper November 2005

2 2 Table of Contents Sun Microsystems, Inc. Table of Contents Introduction to Sun Cluster...3 High Availablity for SAS Metadata Server using Sun Cluster...3 Creating a SAS Metadata Server Data Service for Sun Cluster software...4 Demonstrating High Availability of SAS Metadata Server...5 Conclusion...5 Appendix A: OMRconfig file...6 Appendix B: pingmetadata script...7 Appendix C: Solaris 10 Service Manager for Single-node cluster...7 References...8

3 3 Introduction to Sun Cluster Sun Microsystems, Inc. Introduction to Sun Cluster Sun Cluster software is the industry's premier availability platform for improving the predictability and resilience of mission-critical applications. Sun Cluster software is designed to deliver highly available service levels by providing continuous network, data, and application availability, making recovery from failure transparent to clients. Sun Cluster software automatically restarts a failed resource on the same node if it is healthy or on a backup node if it is not without manual intervention. This enables more predictable application service levels while simultaneously reducing risk and costly outages. The Sun Cluster software extends the Solaris Operating System into a cluster operating system. Key fault detection and recovery functions of the Sun Cluster software are integrated with the operating system, leading to faster failure detection and recovery. A cluster is two or more systems, or nodes, that work together as a single, continuously available system. Each node on a cluster is a fully functional standalone system that runs its own processes. The nodes of a cluster communicate with one another to form what looks like (to a network client) a single system. Failures that would normally bring down a single server system are automatically remediated by the cluster. No single failure hardware, software, or network can cause a cluster to fail. High Availablity for SAS Metadata Server using Sun Cluster Time to intelligence is critical for any business to make quick and accurate, business decisions. The SAS Business Intelligence Server provides an enterprise view of business intelligence. It is critical that this enterprise application and its data are highly available. The foremost component of the SAS 9 architecture which requires high availability is the SAS Metadata Server. The SAS Metadata Server is an in-memory server, which means all queried and updated metadata is held in memory by the server. All modifications to these metadata memory pages are committed to the filesystem storage before completing. If a failure occurs no metadata is lost or corrupted. High availability software like Sun Cluster is required to enable more predictable application service levels and availability of the SAS Metadata Server. The key steps in using Sun Cluster software for SAS Metadata Server high availability is: Cluster hardware configurations and cabling Installing the Solaris Operating System Installing and configuring a volume manager Installing, establishing and configuring Sun Cluster software Installing and configuring SAS Metadata Server software Creating a SAS Metadata Server data service for Sun Cluster Figure 1: Two-node cluster topology For this paper, the assumption is that all but the Creating and installing a SAS Metadata Server data service for Sun Cluster is complete. Figure 1 represents the cluster topology that was used for this exercise. Important elements are: the cluster has two nodes a primary and stand-by; the cluster interconnect for cluster communication; network connections to the LAN; and both nodes connected to a shared storage device. For information on how to setup the cluster, see the Reference section at the end of this paper.

4 4 Creating a SASMetadata Server Data Service for Sun Cluster software Sun Microsystems, Inc. Creating a SAS Metadata Server Data Service for Sun Cluster software As mentioned earlier, each node in a cluster is a fully functional standalone system that has its own network identity a physical hostname. In this case, the primary node s physical hostname is es220a and the stand-by node is es220b. However, SAS does not reference the cluster using the physical hostnames, rather SAS references the cluster by the logical hostname of sas-ms. During this last step of cluster configuration, this logical hostname will be created. This logical hostname will fail-over from the primary cluster node to the stand-by node when a failure occurs to the primary node; thereby, the nodes in the SAS cluster communicate with one another to form what looks like (to a network client) a single system. When the SAS administrator is using the SAS Management Console, the profile s server name would be sas-ms. The summary of the steps to create a SAS Metadata Server data service for Sun Cluster are: Register a resource type Create a failover resource group Add logical hostname to resource group Add a Failover Application Resource to a resource group Bring the resource group and its associated resources online The term data service describes an application, such as the SAS Metadata Server, that has been configured to run on a cluster rather than on a single server. A data service consists of an application, Sun Cluster configuration files, and management methods that control the starting, stopping and monitoring of the application. The Sun Cluster software provides a generic data service. Using this generic data service, a data service for SAS Metadata Server can generated very quickly. The only information needed is the SAS Metadata Server start, stop and monitor methods. For this exercise, the standard SAS Metadata Server start and stop methods were used. To monitor the SAS Metadata Server, the OMRconfig file and the pingmetadataserver script were used (see Appendix A and B). Register the resource type # scrgadm -a -t SUNW.gds -a Adds the specified resource type. -t Specifies the type of resource we are using. In the case, the generic data service Creating a Failover Resource Group # scrgadm -a -g Metadata-harg -h es220a es220b -h Specifies the primary and stand-by physical hostnames that make up the cluster Adding a Logical Hostname Resource to a Resource Group # scrgadm -a -L -g Metadata-harg -l sas-ms -l The logical hostname that the SAS Management Console profile definition will use. Add a Failover Application Resource to a Resource Group # export SASMAIN=/global/sas/d1/CFG/Lev1/SASMain/ # export PROBE_HOME=$SASMAIN/MetadataServer/MetadataExamples/ # export META_HOME=$SASMAIN/MetdataServer # scrgadm -a -g Metadata-harg -t SUNW.gds -j sas-rs \ -x Start_command="$META_HOME/MetadataServer.sh start" \ -x Stop_command="$META_HOME/MetadataServer.sh stop" \ -x Probe_command=$PROBE_HOME/pingMetadataServer.sh \ -y Port_list=8561/tcp -y Network_resources_used=sas-ms

5 5 Creating a SASMetadata Server Data Service for Sun Cluster software Sun Microsystems, Inc. Bringing a Resource Group online # scswitch -Z -g Metadata-harg Table 1: Create SAS Metadata Server monitor for Sun Cluster Demonstrating High Availability of SAS Metadata Server Let s demonstrate that the SAS Metadata Server is now being monitored by Sun Cluster and is highly available. In Table 2 section, the following actions will be taken: Display the status of the cluster Verify that the SAS Metadata Server is running Kill the SAS Metadata Server simulating a hardware or software failure Verify that the Sun Cluster software restarts the SAS Metadata Server Display the status of the cluster; es220a is primary and online root@es220a # scstat -g Group Name Node Name State Group: Metadata-harg es220a Online Group: Metadata-harg es220b Offline Verify that the SAS Metadata Server is running root@es220a # ps -ef grep Meta root /global/sas/d1/sas/sasexe/sas -log /global/sas/d1/cfg/lev1/sasmain/metadataserver... root gds_svc_start -R sas-rs -G Metadata-harg root /bin/sh./metadataserver/metadataserver.sh start2 Kill the SAS Metadata Server simulating a hardware or software failure root@es220a # kill root@es220a # ps -ef grep Meta root :22:53 pts/2 0:00 grep Meta Verify that the SAS Metadata Server is running on es220b root@es220a # scstat -g Group Name Node Name State Group: Metadata-harg es220a Offline Group: Metadata-harg es220b Online Table 2: Demonstrating HA SAS Metadata Server using Sun Cluster In the case of a simple software failure, Sun Cluster can be used to restart the Metadata Server on the same node of the cluster. However, for this paper the exit status, called the probe status, is set to 201, which causes the application to immediately fail over. See Appendix B for more details. Conclusion Business Intelligence is a business-critical, enterprise application. As customers move from a best of breed, departmental BI tools to an enterprise-class, intelligence platform from SAS, the SAS Metadata Server is central to that intelligence platform and provides centralized, enterprise-wide metadata management. Customers in every industry have concerns about any downtime of their SAS environment because downtime can mean lost productivity, revenue, customers and opportunities. The SAS Metadata Server provides services to all SAS applications in the enterprise supporting multiple repositories and thousands of concurrent users. For this reason alone, the SAS Metadata Server requires high-availability. This papers purpose is to demonstrate how Sun Cluster Software, which extends the Solaris Operating System into a cluster operating system, is designed to deliver highly available service levels for the SAS Metadata Server. Sun Cluster improves the service-level and resilience of SAS as a mission.critical application making recovery from failures transparent to clients.

6 6 Appendix A: OMRconfig file Sun Microsystems, Inc. Appendix A: OMRconfig file <?xml version="1.0" encoding="utf-8"?> <Redirect> <LogicalServer Name="SAS Metadata Server" ClassIdentifier="2887E7D D4-879F-00C04F38F0DB"> <UsingComponents> <ServerComponent Name="SAS Metadata Server" ClassIdentifier="2887E7D D4-879F-00C04F38F0DB"> <SourceConnections> <TCPIPConnection Name="SAS Metadata Server" ApplicationProtocol="Bridge" CommunicationProtocol="TCP" HostName="sas-ms" Port="8561"> <Domain> <Logins> <AuthenticationDomain Name="DefaultAuth"> <Login Name="sasadm" UserId="sasadm" Password="sunone01" /> </Logins> </AuthenticationDomain> </Domain> <Properties> <Property Name="Repository" PropertyName="Repository" DefaultValue="Foundation" /> </Properties> </TCPIPConnection> </SourceConnections> </ServerComponent> </UsingComponents> </LogicalServer> </Redirect>

7 7 Appendix B: pingmetadata script Sun Microsystems, Inc. Appendix B: pingmetadata script #!/usr/bin/ksh # The location that the necessary jars were installed export utildir=/global/sas/d1/cfg/lev1/sasmain/metadataserver/metadataexamples/ # # Run a quick program to get the status. java -jar "$utildir/lib/sas.metadata.utilities.jar" -config "$utildir/config/omrconfig.xml" \ -inxml "$utildir/pingmetadataserver/xml/getstatus.xml" \ -inxsl "$utildir/pingmetadataserver/styles/getstatusresult.xsl" \ -log "$utildir/pingmetadataserver/logs/getstatus.log" -exitstatus -debug exitval=$? echo $exitval if (($exitval == 0)); then status=$exitval else status=201 #echo "SAS Metadata Server failure Restarting Metadata Server" fi echo $status exit 0 The pingmetadata is provided courtesy of SAS R&D. The pingmetadata command periodically checks the health of the SAS Metadata Server. The probe command returns with an exit status of 0 if the application is running correctly. The exit status of the probe command is used to determine the severity of the application's failure. This exit status, called the probe status, must be an integer between 0 (for success) and 100 (for complete failure). The probe status can also be a special value of 201, which causes the application to immediately fail over unless Failover_enabled is set to FALSE. The GDS probing algorithm uses the probe status to determine whether to restart the application locally or fail it over. See the scds_fm_action(3ha) man page for more information. If the exit status is 201, the application is immediately failed over. Appendix C: Solaris 10 Service Manager for Single-node cluster Solaris 10 Service Manager for Single-node cluster: Self healing for Applications Solaris 10 Service manager is a feature to enable services to be more robust, reliable and easier to manage. It is a core part of the Predictive Self-Healing technology available in Solaris 10, which provides automatic recovery from software and hardware failures. Failed services are restarted in dependency order. The services can be started using an XML manifest. In the manifest you tell it how to start it, what its dependencies are, and how to stop it. If SAS has a software error and terminates, Solaris Service Manager will restart SAS using the XML manifest. If hardware fails SAS will restart when the system reboots.

8 8 References Sun Microsystems, Inc. References Sun Cluster Overview for Solaris OS Sun Cluster Software Quality by Design for Advanced Availability Sun Cluster Software Installation Guide for Solaris OS Sun Cluster System Administration Guide for Solaris OS Sun Cluster Hardware Collection for Solaris OS SAS Open Metadata Architecture: Best Practices Guide, Second Edition SAS Metadata Server: Setup and Administration Guide, Third Edition

9 9 References Sun Microsystems, Inc. References System Administration Guide: Solaris Containers Resource Management and Solaris Zones Internal Zone configuration Solaris 10 - In a class by itself Solaris Containers Whitepaper Sun Solaris Containers vs. IBM Logical Partitions and HP Virtual Partitions

10 10 References Sun Microsystems, Inc. Sun Microsystems, Inc. Network Circle, Santa Clara, CA USA Phone or SUN Web sun.com 2005 Sun Microsystems, Inc. All right reserved Sun, Sun Microsystems, the Sun logo [insert all other Sun Product Names, Service Names, Program Names, Special Programs Logos and slogans listed in Tmark and referred to or displayed in the document] are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries."